1. Field of the Invention
The present invention relates to a dental alginate impression material composition used for taking the impression inside an oral cavity at the time of producing a prosthesis in a dental treatment.
2. Description of the Conventional Art
In a dental treatment, a dental alginate impression material has been widely used as an impression material for taking an impression of an oral cavity at the time of producing a prosthesis of a damaged portion in an oral cavity. Although an alginate impression material is a powder-like material or a paste-like material depending on the form of a product, a powder-like alginate impression material has been widely used since cost is low and an application area is wide. The present invention relates to the powder-like alginate impression material. Powder of an alginate impression material mainly include alginate, a gelatinizing reactant, a gelatinizing regulator, and a filler, and the powder is kneaded with water so as to be gelatinized and cured.
An alginate impression material is used by mixing and kneading powder with water so as to be gelatinized, taking it into an oral cavity, and curing it. At this time, the permeation speed of water with respect to the powder of an alginate impression material is slow, so that it takes much time to permeate water to the whole powder. Thus, since a kneading time is long, a sufficient operational time cannot be secured. Further, when powder of an alginate impression material is kept for a long period of time, the powder components are changed in quality with time. Thus, when such a material obtained by kneading powder of an alginate impression material with water is used in an oral cavity, the kneaded material easily drops. So, the dental impression material has a big problem that a kneaded material easily drops to a throat of a patient who faces up.
In order solve such problems, for example, Japanese Patent Application Laid Open No. 2002-104916 discloses a powder-like alginate impression material having excellent initial affinity for water, where the material includes bacillary diatomaceous earth, and polyoxyethylene aliphatic ether as a specific surfactant. However, this alginate impression material can improve initial affinity for water, but cannot improve the permeation speed of water, so that the kneading time is not shortened. Further, in order to solve the problem that an alginate impression material easily drops, an impression material including polysaccharides, such as carrageenan, pullulan, and the like, so as to make the material to hardly drop is disclosed, where the polysaccharides are also disclosed in the present invention. However, this invention improves the dropping problem of a material by a kneading condition (a ratio of powders to water), but does not solve a problem that a kneaded material drops due to aging.